@mixin border-1px($color) {
    position: relative;
    &:after{
        display: block;
        position: absolute;
        left: 0px;
        bottom: 0px;
        width: 100%;
        border-top: 1px solid $color;
        content: ' ';
    }
}

@mixin bg-image($url){
    background-image:url($url+"@2x.png");
    @media (-webkit-min-device-pixel-ratio:3),(min-device-pixel-ratio:3){
       background-image:url($url+"@3x.png");
    } 
}